Systemd初始化进程服务
RHEL 6 RHEL 7
service foo start systemctl start foo.service 启动服务
service foo restart systemctl restart foo.service 重启服务
service foo stop systemctl stop foo.service 停止服务
service foo reload systemctl reload foo.service 重启加载配置文件（不终止服务）
service foo status systemctl status foo.service 查看服务状态
chkconfig foo on systemctl enable foo.service 开机自启动
chkconfig foo off systemctl disable foo.service 开机不自启动
chkconfig foo systemctl is-enabled foo.service 查看服务开机是否自启动
.service 可以省略
